1. Field of the Invention
The present invention relates to the general technical field of agricultural machinery and in particular to a haymaking machine that can be hitched to a tractor and comprises a frame carrying a cutting mechanism comprising cutting tools and a carrying structure intended to support a protective device, said protective device consisting of at least one central protector.
2. Discussion of the Background
Haymaking machines are for example cutting machines of the rotary mower, mower-crusher with one or more vertical axes or with horizontal axis type. Known rotary mowers comprise a cutting mechanism with cutting tools in the form of disks or drums. These disks or drums cut standing product, for example grass, by means of rotary knives rotating at high speed. The mowers are protected in order to prevent any contact with the rotating cutting tools at the front, at the rear, at the sides and at the top. The protective device masks the cutting tools and prevents earth and even stones being thrown out. The protective device therefore comprises at least one central protector, at least one rear protector and a side protector on either side. During work, the knives wear and may also be damaged by an obstacle. A conventional maintenance operation is therefore the replacement of these knives. This operation is usually carried out when the cutting mechanism is clear of the ground, which makes the work easier.
Such a machine is, for example, a trailed mower-conditioner. This mower comprises a cutting mechanism connected to a frame which rests on the ground via wheels. It is hitched to a tractor via a drawbar which is connected to the frame and which extends at least partially above the cutting mechanism. The drawbar carries drive members enabling the tools of the cutting mechanism to rotate. The cutting mechanism comprises a carrying structure and a protective device. The carrying structure supports the protective device and the latter covers the cutting mechanism. The protective device comprises a central protector which protects the portion in front of and the portion above the cutting tools. Regulations lay down a minimum distance for this central protector above and in front of the cutting tools.
To gain access to the cutting tools and make maintenance work easier, the central protector is moved away. On this machine, the central protector is connected to the carrying structure by means of an articulation with a substantially horizontal axis that is perpendicular to the direction of travel. This articulation extends above the cutting mechanism. The movement away is therefore carried out by pivoting about this articulation. When the cutting mechanism is moved away from the ground, it can be noted that the articulation is arranged in the vicinity of the drawbar and of the transmission member and that it is therefore no longer possible to pivot the central protector about the articulation. The central protector is therefore moved away starting from the work position when the cutting mechanism is close to the ground. This condition requires the user to carry out various actions. Thus, he has to get down from the tractor, move away the central protector by pivoting it about the articulation, then he has to get back into the tractor, move the cutting mechanism away from the ground and finally he must get down again from the tractor to carry out the maintenance operation. When the latter is complete, the user carries out the procedure described above in reverse so that the mower is again operational. It can therefore be seen that to gain access to the cutting tools is a tiresome operation requiring getting on and off the tractor many times and is costly in time.
On another machine, the central protector is moved away by pivoting it about an articulation with a substantially vertical axis. The vertical articulation is arranged in front and at one end of the central protector. The pivoting is carried out manually by raising the central protector via the other end. It is possible to move the central protector fully away only when the drawbar extends laterally or is moved away to one side in the case of a central drawbar. The moved end of the central protector is supported by a stand. The central protector is swung open when the cutting mechanism is close to the ground. In this position close to the ground, the opening of the central protector is made easier, however the user does not enjoy optimal conditions for replacing the knives.